Energy efficiency using beamforming at the base station in UMTS and LTE

The race for energy aware systems is motivating the development of solutions that reduce the overall power consumption in telecommunication systems. In this paper, one studies the use of beamforming from an energy efficiency viewpoint in UMTS and LTE. Several user scenarios, with different users´ arrangements, were studied. Models were implemented to evaluate the potential impact that adaptive antennas can have to reduce the radiated power, compared to the current use of base station static sector antennas. With the use of beamforming, UMTS has a lot of interference suppression potential, besides signal improvement, enabling quite an increase in energy efficiency; LTE, due to the different multiple access technique, presents a different behaviour, coming from signal improvement. Through a statistical analysis, a model for UMTS that describes the achievable energy improvement as a function of the number of users and antennas is derived. For UMTS with carriers near top capacity, an energy reduction of 90% is achieved. For LTE, significant energy improvements are reached, 65% saving being obtained with 8 antennas.